As is known in the art, there is a class of microwave antennas referred to as Multiple Beam Antennas (MBAs). Receive MBAs use reflectors and lenses to provide large antenna apertures with relatively low element count Multiple Beam Feeds (MBFs) to provide multiple beam outputs with electronic steering. MBFs produce this electronic steering by electronically changing interconnects between multiple radiating elements that do not cover the full antenna aperture and multiple beams. MBA MBFs have much lower element counts than those of equivalent aperture direct radiating electronically steered antennas (ESAs), which have elements that cover the full antenna aperture.
There are two types of MBFs, a first type having analog beamformers and a second type having digital beamformers. With respect to the first type, the circuitry of MBFs having analog beamformers can be very complex. Analog MBF's may use either a complex microwave matrix switch (MSM) approach or a complex phased array feed (PAF) approach to electronically change interconnects between elements and beams. In a system having 1270 antenna elements, for example, the MSM approach may use 100,000-200,000 microwave switches, 80 microwave power summers (e.g., 1270:1 power summers), 1,270 microwave power dividers (e.g., 1:80 power dividers), and a complex microwave interconnect topology. The PAF approach may use 5,080 phasors and attenuators, and 4 element summing manifolds (e.g., 1270:1 summing manifolds). Thus, both the MSM approach and the PAF approach require large analog components counts and complex topologies, which increase the size, weight, DC power, and cost of such MBF's.